convert to withCreateProcess for async exception safety

This handles all sites where checkSuccessProcess/ignoreFailureProcess
is used, except for one: Git.Command.pipeReadLazy
That one will be significantly more work to convert to bracketing.

(Also skipped Command.Assistant.autoStart, but it does not need to
shut down the processes it started on exception because they are
git-annex assistant daemons..)

forceSuccessProcess is done, except for createProcessSuccess.
All call sites of createProcessSuccess will need to be converted
to bracketing.

(process pools still todo also)

Annex/YoutubeDl.hs

@@ -205,12 +205,14 @@ youtubeDlFileNameHtmlOnly' url uo
 			, Param "--no-warnings"
 			, Param "--no-playlist"
 			]
-		(Nothing, Just o, Just e, pid) <- liftIO $ createProcess
-			(proc "youtube-dl" (toCommand opts))
-				{ std_out = CreatePipe
-				, std_err = CreatePipe
-				}
-		output <- liftIO $ fmap fst $ 
+		let p = (proc "youtube-dl" (toCommand opts))
+			{ std_out = CreatePipe
+			, std_err = CreatePipe
+			}
+		liftIO $ withCreateProcess p waitproc
+	
+	waitproc Nothing (Just o) (Just e) pid = do
+		output <- fmap fst $ 
 			hGetContentsStrict o
 				`concurrently`
 			hGetContentsStrict e
@@ -218,6 +220,8 @@ youtubeDlFileNameHtmlOnly' url uo
 		return $ case (ok, lines output) of
 			(True, (f:_)) | not (null f) -> Right f
 			_ -> nomedia
+	waitproc _ _ _ _ = error "internal"
+
 	nomedia = Left "no media in url"
 
 youtubeDlOpts :: [CommandParam] -> Annex [CommandParam]

Assistant/Restart.hs

@@ -113,7 +113,5 @@ assistantListening url = catchBoolIO $ do
 startAssistant :: FilePath -> IO ()
 startAssistant repo = void $ forkIO $ do
 	program <- programPath
-	(_, _, _, pid) <- 
-		createProcess $
-			(proc program ["assistant"]) { cwd = Just repo }
-	void $ checkSuccessProcess pid
+	let p = (proc program ["assistant"]) { cwd = Just repo }
+	withCreateProcess p $ \_ _ _ pid -> void $ checkSuccessProcess pid

Assistant/Threads/RemoteControl.hs

@@ -32,20 +32,27 @@ remoteControlThread = namedThread "RemoteControl" $ do
 	(cmd, params) <- liftIO $ toBatchCommand
 		(program, [Param "remotedaemon", Param "--foreground"])
 	let p = proc cmd (toCommand params)
-	(Just toh, Just fromh, _, pid) <- liftIO $ createProcess p
+	bracket (setup p) cleanup (go p)
+  where
+	setup p = liftIO $ createProcess $ p
 		{ std_in = CreatePipe
 		, std_out = CreatePipe
 		}
-	
-	urimap <- liftIO . newMVar =<< liftAnnex getURIMap
+	cleanup = liftIO . cleanupProcess
 
-	controller <- asIO $ remoteControllerThread toh
-	responder <- asIO $ remoteResponderThread fromh urimap
+	go p (Just toh, Just fromh, _, pid) = do
+		urimap <- liftIO . newMVar =<< liftAnnex getURIMap
 
-	-- run controller and responder until the remotedaemon dies
-	liftIO $ void $ tryNonAsync $ controller `concurrently` responder
-	debug ["remotedaemon exited"]
-	liftIO $ forceSuccessProcess p pid
+		controller <- asIO $ remoteControllerThread toh
+		responder <- asIO $ remoteResponderThread fromh urimap
+
+		-- run controller and responder until the remotedaemon dies
+		liftIO $ void $ tryNonAsync $
+			controller `concurrently` responder
+		debug ["remotedaemon exited"]
+		liftIO $ forceSuccessProcess p pid	
+	go _ _ = error "internal"
+		
 
 -- feed from the remoteControl channel into the remotedaemon
 remoteControllerThread :: Handle -> Assistant ()

Git/CatFile.hs

@@ -180,14 +180,16 @@ querySingle o r repo reader = assertLocal repo $
 			, std_in = Inherit
 			, std_out = CreatePipe
 			}
-		pid <- createProcess p'
-		let h = stdoutHandle pid
-		output <- reader h
-		hClose h
-		ifM (checkSuccessProcess (processHandle pid))
+		withCreateProcess p' go
+  where
+	go _ (Just outh) _ pid = do
+		output <- reader outh
+		hClose outh
+		ifM (checkSuccessProcess pid)
 			( return (Just output)
 			, return Nothing
 			)
+	go _ _ _ _ = error "internal"
 
 querySize :: Ref -> Repo -> IO (Maybe FileSize)
 querySize r repo = maybe Nothing (readMaybe . takeWhile (/= '\n'))

Git/Command.hs

@@ -1,6 +1,6 @@
 {- running git commands
  -
- - Copyright 2010-2013 Joey Hess <id@joeyh.name>
+ - Copyright 2010-2020 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -70,13 +70,17 @@ pipeReadStrict = pipeReadStrict' S.hGetContents
 
 {- The reader action must be strict. -}
 pipeReadStrict' :: (Handle -> IO a) -> [CommandParam] -> Repo -> IO a
-pipeReadStrict' reader params repo = assertLocal repo $
-	withHandle StdoutHandle (createProcessChecked ignoreFailureProcess) p $ \h -> do
-		output <- reader h
-		hClose h
-		return output
+pipeReadStrict' reader params repo = assertLocal repo $ withCreateProcess p go
   where
-	p  = gitCreateProcess params repo
+	p  = (gitCreateProcess params repo)
+		{ std_out = CreatePipe }
+
+	go _ (Just outh) _ pid = do
+		output <- reader outh
+		hClose outh
+		void $ waitForProcess pid
+		return output
+	go _ _ _ _ = error "internal"
 
 {- Runs a git command, feeding it an input, and returning its output,
  - which is expected to be fairly small, since it's all read into memory

Git/Fsck.hs

@@ -77,27 +77,31 @@ findBroken batchmode r = do
 		then toBatchCommand (command, params)
 		else return (command, params)
 	
-	p@(_, _, _, pid) <- createProcess $
-		(proc command' (toCommand params'))
-			{ std_out = CreatePipe
-			, std_err = CreatePipe
-			}
-	(o1, o2) <- concurrently
-		(parseFsckOutput maxobjs r (stdoutHandle p))
-		(parseFsckOutput maxobjs r (stderrHandle p))
-	fsckok <- checkSuccessProcess pid
-	case mappend o1 o2 of
-		FsckOutput badobjs truncated
-			| S.null badobjs && not fsckok -> return FsckFailed
-			| otherwise -> return $ FsckFoundMissing badobjs truncated
-		NoFsckOutput
-			| not fsckok -> return FsckFailed
-			| otherwise -> return noproblem
-		-- If all fsck output was duplicateEntries warnings,
-		-- the repository is not broken, it just has some unusual
-		-- tree objects in it. So ignore nonzero exit status.
-		AllDuplicateEntriesWarning -> return noproblem
+	let p = (proc command' (toCommand params'))
+		{ std_out = CreatePipe
+		, std_err = CreatePipe
+		}
+	withCreateProcess p go
   where
+	go _ (Just outh) (Just errh) pid = do
+		(o1, o2) <- concurrently
+			(parseFsckOutput maxobjs r outh)
+			(parseFsckOutput maxobjs r errh)
+		fsckok <- checkSuccessProcess pid
+		case mappend o1 o2 of
+			FsckOutput badobjs truncated
+				| S.null badobjs && not fsckok -> return FsckFailed
+				| otherwise -> return $ FsckFoundMissing badobjs truncated
+			NoFsckOutput
+				| not fsckok -> return FsckFailed
+				| otherwise -> return noproblem
+			-- If all fsck output was duplicateEntries warnings,
+			-- the repository is not broken, it just has some
+			-- unusual tree objects in it. So ignore nonzero
+			-- exit status.
+			AllDuplicateEntriesWarning -> return noproblem
+	go _ _ _ _ = error "internal"
+	
 	maxobjs = 10000
 	noproblem = FsckFoundMissing S.empty False
 

Git/UpdateIndex.hs

@@ -136,15 +136,7 @@ indexPath = toInternalGitPath . getTopFilePath
 
 {- Refreshes the index, by checking file stat information.  -}
 refreshIndex :: Repo -> ((FilePath -> IO ()) -> IO ()) -> IO Bool
-refreshIndex repo feeder = do
-	(Just h, _, _, p) <- createProcess (gitCreateProcess params repo)
-		{ std_in = CreatePipe }
-	feeder $ \f -> do
-		hPutStr h f
-		hPutStr h "\0"
-	hFlush h
-	hClose h
-	checkSuccessProcess p
+refreshIndex repo feeder = withCreateProcess p go
   where
 	params = 
 		[ Param "update-index"
@@ -153,3 +145,15 @@ refreshIndex repo feeder = do
 		, Param "-z"
 		, Param "--stdin"
 		]
+	
+	p = (gitCreateProcess params repo)
+		{ std_in = CreatePipe }
+
+	go (Just h) _ _ pid = do
+		feeder $ \f -> do
+			hPutStr h f
+			hPutStr h "\0"
+		hFlush h
+		hClose h
+		checkSuccessProcess pid
+	go _ _ _ _ = error "internal"

Remote/Bup.hs

@@ -164,10 +164,16 @@ store r buprepo = byteStorer $ \k b p -> do
 retrieve :: BupRepo -> Retriever
 retrieve buprepo = byteRetriever $ \k sink -> do
 	let params = bupParams "join" buprepo [Param $ bupRef k]
-	let p = proc "bup" (toCommand params)
-	(_, Just h, _, pid) <- liftIO $ createProcess $ p { std_out = CreatePipe }
-	liftIO (hClose h >> forceSuccessProcess p pid)
-		`after` (sink =<< liftIO (L.hGetContents h))
+	let p = (proc "bup" (toCommand params))
+		{ std_out = CreatePipe }
+	bracketIO (createProcess p) cleanupProcess (go sink p)
+  where
+	go sink p (_, Just h, _, pid) = do
+		() <- sink =<< liftIO (L.hGetContents h)
+		liftIO $ do
+			hClose h
+			forceSuccessProcess p pid
+	go _ _ _ = error "internal"
 
 {- Cannot revert having stored a key in bup, but at least the data for the
  - key will be used for deltaing data of other keys stored later.

Remote/Ddar.hs

@@ -157,10 +157,16 @@ ddarExtractRemoteCall cs ddarrepo k =
 retrieve :: DdarRepo -> Retriever
 retrieve ddarrepo = byteRetriever $ \k sink -> do
 	(cmd, params) <- ddarExtractRemoteCall NoConsumeStdin ddarrepo k
-	let p = (proc cmd $ toCommand params) { std_out = CreatePipe }
-	(_, Just h, _, pid) <- liftIO $ createProcess p
-	liftIO (hClose h >> forceSuccessProcess p pid)
-		`after` (sink =<< liftIO (L.hGetContents h))
+	let p = (proc cmd $ toCommand params)
+		{ std_out = CreatePipe }
+	bracketIO (createProcess p) cleanupProcess (go sink p)
+  where
+	go sink p (_, Just h, _, pid) = do
+		() <- sink =<< liftIO (L.hGetContents h)
+		liftIO $ do
+			hClose h
+			forceSuccessProcess p pid
+	go _ _ _ = error "internal"
 
 remove :: DdarRepo -> Remover
 remove ddarrepo key = do

Remote/Glacier.hs

@@ -185,14 +185,15 @@ retrieve' r k sink = go =<< glacierEnv c gc u
 		]
 	go Nothing = giveup "cannot retrieve from glacier"
 	go (Just environ) = do
-		let cmd = (proc "glacier" (toCommand params))
+		let p = (proc "glacier" (toCommand params))
 			{ env = Just environ
 			, std_out = CreatePipe
 			}
-		(_, Just h, _, pid) <- liftIO $ createProcess cmd
+		bracketIO (createProcess p) cleanupProcess (go' p)
+	go' p (_, Just h, _, pid) = do
 		let cleanup = liftIO $ do
 			hClose h
-			forceSuccessProcess cmd pid
+			forceSuccessProcess p pid
 		flip finally cleanup $ do
 			-- Glacier cannot store empty files, so if
 			-- the output is empty, the content is not
@@ -200,6 +201,7 @@ retrieve' r k sink = go =<< glacierEnv c gc u
 			whenM (liftIO $ hIsEOF h) $
 				giveup "Content is not available from glacier yet. Recommend you wait up to 4 hours, and then run this command again."
 			sink =<< liftIO (L.hGetContents h)
+	go' _ _ = error "internal"
 
 remove :: Remote -> Remover
 remove r k = unlessM go $

Utility/Gpg.hs

@@ -171,16 +171,19 @@ pipeLazy (GpgCmd cmd) params feeder reader = do
 		, std_out = CreatePipe
 		, std_err = Inherit
 		}
-	bracket (setup p) (cleanup p) go
+	bracket (setup p) cleanup (go p)
   where
 	setup = liftIO . createProcess
-	cleanup p (_, _, _, pid) = liftIO $ forceSuccessProcess p pid
-	go p = do
-		let (to, from) = ioHandles p
+	cleanup = liftIO . cleanupProcess
+
+	go p (Just to, Just from, _, pid) = do
 		liftIO $ void $ forkIO $ do
 			feeder to
 			hClose to
-		reader from
+		r <- reader from
+		liftIO $ forceSuccessProcess p pid
+		return r
+	go _ _ = error "internal"
 
 {- Finds gpg public keys matching some string. (Could be an email address,
  - a key id, or a name; See the section 'HOW TO SPECIFY A USER ID' of

Utility/Lsof.hs

@@ -49,11 +49,16 @@ queryDir path = query ["+d", path]
  - Note: If lsof is not available, this always returns [] !
  -}
 query :: [String] -> IO [(FilePath, LsofOpenMode, ProcessInfo)]
-query opts =
-	withHandle StdoutHandle (createProcessChecked checkSuccessProcess) p $
-		parse <$$> hGetContentsStrict
+query opts = withCreateProcess p go
   where
-	p = proc "lsof" ("-F0can" : opts)
+	p = (proc "lsof" ("-F0can" : opts))
+		{ std_out = CreatePipe }
+	
+	go _ (Just outh) _ pid = do
+		r <- parse <$> hGetContentsStrict outh
+		void $ waitForProcess pid
+		return r
+	go _ _ _ _ = error "internal"
 
 type LsofParser = String -> [(FilePath, LsofOpenMode, ProcessInfo)]
 

Utility/Process.hs

@@ -20,7 +20,6 @@ module Utility.Process (
 	forceSuccessProcess,
 	forceSuccessProcess',
 	checkSuccessProcess,
-	ignoreFailureProcess,
 	createProcessSuccess,
 	createProcessChecked,
 	createBackgroundProcess,
@@ -53,7 +52,6 @@ import System.Log.Logger
 import Control.Monad.IO.Class
 import Control.Concurrent
 import qualified Control.Exception as E
-import Control.Monad
 import qualified Data.ByteString as S
 
 type CreateProcessRunner = forall a. CreateProcess -> ((Maybe Handle, Maybe Handle, Maybe Handle, ProcessHandle) -> IO a) -> IO a
@@ -135,11 +133,6 @@ checkSuccessProcess pid = do
 	code <- waitForProcess pid
 	return $ code == ExitSuccess
 
-ignoreFailureProcess :: ProcessHandle -> IO Bool
-ignoreFailureProcess pid = do
-	void $ waitForProcess pid
-	return True
-
 -- | Runs createProcess, then an action on its handles, and then
 -- forceSuccessProcess.
 createProcessSuccess :: CreateProcessRunner